The present invention is directed to enclosures of underground structures commonly employed by power and water utilities, such as transformers, generators, pumps and the like. More specifically, the invention relates to a unique locking mechanism for underground vaults which house these structures.
Hardware, such as transformers, employed by utilities, is often buried underground in vaults for protection and space conservation. Typically, these vaults are formed of essentially cylindrical top and bottom sections with each having an open end of essentially the same diameter. The open ends are placed in mutual confrontation to form an enclosure about the transformer. The bottom of the enclosure is covered with a grate, and the enclosure with transformer is buried in the ground. The top, which is open, is covered with a frusto-conical cap which extends above ground level. This cap is in turn covered with a grate. Thus, although the transformer is safely protected below ground level, maintenance personnel have access to the structure through the open top when necessary.
The two sections of the vault must be securely locked together. Yet, it is preferable that the lock not be permanent so that the sections may be separated if desired. In the past, these sections have been secured by nails extending through the periphery of the two sections. Such a mechanism has proven unsatisfactory since the nails tend to rust and deteriorate when beneath the ground, causing a weakening of the bond.
U.S. Pat. No. 4,065,020, issued to Carson, discloses the use of legs which project downward from the top section and fit into slots in the bottom section. Such a mechanism does not provide the necessary holding strength.
Thus, there is a need for a vault whose sections are simply, yet securely locked together without the possibility of accidental separation. Moreover, this bond, although strong, should not be permanent and should be detachable without damage to the vault section.